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CVE-2021-31955

Microsoft Windows Kernel Information Disclosure

5.5 MEDIUMActively exploited (CISA KEV)EPSS 81.1%
  1. Published8 Jun 2021
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due17 Nov 2021
Actively exploited (CISA KEV)

Microsoft Windows Kernel contains an unspecified vulnerability that allows for information disclosure. Successful exploitation allows attackers to read the contents of kernel memory from a user-mode process.

Added to KEV: 3 Nov 2021Federal remediation due: 17 Nov 2021

Description

Windows Kernel Information Disclosure Vulnerability

CVSS 3.1 breakdown

Attack vectorLocal
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

Microsoft Windows 10 1809< 10.0.17763.1999
Microsoft Windows 10 1909< 10.0.18363.1621
Microsoft Windows 10 2004< 10.0.19041.1052
Microsoft Windows 10 20h2< 10.0.19042.1052
Microsoft Windows 10 21h1< 10.0.19043.1052
Microsoft Windows Server 2004< 10.0.19041.1052
Microsoft Windows Server 2019< 10.0.17763.1999
Microsoft Windows Server 20h2< 10.0.19042.1052

Remediation

Fixed in
Microsoft Windows 10 1809≥ 10.0.17763.1999
Microsoft Windows 10 1909≥ 10.0.18363.1621
Microsoft Windows 10 2004≥ 10.0.19041.1052
Microsoft Windows 10 20h2≥ 10.0.19042.1052
Microsoft Windows 10 21h1≥ 10.0.19043.1052
Microsoft Windows Server 2004≥ 10.0.19041.1052
Microsoft Windows Server 2019≥ 10.0.17763.1999
Microsoft Windows Server 20h2≥ 10.0.19042.1052

References

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Frequently asked

Is CVE-2021-31955 being actively exploited?

Yes. CVE-2021-31955 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021.

How severe is CVE-2021-31955?

CVE-2021-31955 has a CVSS 3.1 base score of 5.5, rated medium. EPSS estimates a 81.1% probability of exploitation.

Which products are affected by CVE-2021-31955?

Affected products include Microsoft Windows 10 1809, Microsoft Windows 10 1909, Microsoft Windows 10 2004, Microsoft Windows 10 20h2, Microsoft Windows 10 21h1, and 3 more.

How do I fix CVE-2021-31955?

Upgrade affected software to a fixed version, for example Microsoft Windows 10 1809 10.0.17763.1999, Microsoft Windows 10 1909 10.0.18363.1621, Microsoft Windows 10 2004 10.0.19041.1052 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-31955 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.